The invention relates generally to well drilling tools and more particularly to self-stabilizing drilling tools, that is tools that drill vertical holes or return to vertical when displaced therefrom.
The invention is an improvement on my prior inventions in the same field on which U.S. Pat. Nos. 3,799,279 and 3,880,246 have been issued. In those patents apparatus and method of using were disclosed for changing the direction of drilling either to deviate from the vertical or bring back to vertical.
In the present invention the conventional bit is kept vertical through minute oscillations provided by the tool acted on by the force of gravity and the application of leverage, while drilling continues.